 /*******************************************************************************
  * Copyright (c) 2003, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.navigator;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.ui.navigator.ICommonLabelProvider;
 import org.eclipse.ui.navigator.IDescriptionProvider;

 /**
  *
  * <p>
  * <strong>EXPERIMENTAL</strong>. This class or interface has been added as
  * part of a work in progress. There is a guarantee neither that this API will
  * work nor that it will remain the same. Please do not use this API without
  * consulting with the Platform/UI team.
  * </p>
  *
  * @since 3.2
  *
  */
 public final class NavigatorContentServiceDescriptionProvider implements
         IDescriptionProvider {

     private final NavigatorContentService contentService;

     /**
      * Creates a description provider that targets the given service.
      *
      * @param aContentService
      * The content service associated with this provider.
      */
     public NavigatorContentServiceDescriptionProvider(
             NavigatorContentService aContentService) {
         Assert.isNotNull(aContentService);
         contentService = aContentService;
     }

     public String getDescription(Object anElement) {

         Object target;

         if (anElement instanceof IStructuredSelection) {

             IStructuredSelection structuredSelection = (IStructuredSelection) anElement;
             if (structuredSelection.size() > 1) {
                 return getDefaultStatusBarMessage(structuredSelection.size());
             }
             target = structuredSelection.getFirstElement();
         } else {
             target = anElement;
         }
         String message = null;
         ILabelProvider[] providers = contentService
                 .findRelevantLabelProviders(target);
         if (providers.length == 0) {
             return getDefaultStatusBarMessage(0);
         }
         for (int i = 0; i < providers.length && (message == null || message.length() == 0); i++) {
             if (providers[i] instanceof ICommonLabelProvider) {
                 message = ((ICommonLabelProvider) providers[i])
                         .getDescription(target);
             }
         }
         message = (message != null) ? message : getDefaultStatusBarMessage(1);
         return message;

     }

     /**
      * @param aSize
      * The number of items selected.
      * @return A string of the form "# items selected"
      */
     protected final String getDefaultStatusBarMessage(int aSize) {
         return NLS.bind(
                 CommonNavigatorMessages.Navigator_statusLineMultiSelect,
                 new Object [] { new Integer (aSize) });

     }

 }

